As a relatively complex virus, EBV is not yet fully understood. Laboratories around the world continue to study the virus and develop new ways to treat the diseases it causes. One popular way of studying EBV in vitro is to use bacterial artificial chromosomes .  Epstein–Barr virus can be maintained and manipulated in the laboratory in continual latency (a property shared with Kaposi's sarcoma-associated herpesvirus , another of the eight human herpesviruses). Although many viruses are assumed to have this property during infection of their natural hosts, there is not an easily managed system for studying this part of the viral lifecycle. Genomic studies of EBV have been able to explore lytic reactivation and regulation of the latent viral episome. 
Infectious mononucleosis , or " mono " as it is commonly referred to, is a viral illness that causes extreme fatigue , fever , muscle aches, swollen lymph nodes , and sore throat . It is sometimes called “the kissing disease” because it spreads easily through saliva. The Epstein-Barr virus (EBV) causes most cases of mono, although other viruses may cause the illness. Severe cases of mono may cause inflammation of the liver or spleen. If the spleen is enlarged, it is important to avoid vigorous physical activity and contact sports to reduce the risk of spleen rupture.